The present invention relates to a toothbrush.
It is known that for dental hygiene it would be desirable to brush the teeth after each meal. Modern life hardly lends itself to such obligations, as most active people take their lunchtime meal away from their home, in a canteen, restaurant, etc.
The document FR-2 537 856 (VIVES) discloses a toothbrush that can be carried and used easily anywhere.
The toothbrush has a body formed of a hollow handle adapted to be filled with toothpaste and a brush member with lateral bristles in the vicinity of the end of the handle, which is formed of two parts having at their corresponding ends means for fixing them together end-to-end, the first part having bristles and the second part forming a reservoir for the toothpaste and having at one end an outflow hole for the toothpaste and at the other end means for actuating a piston housed in the reservoir and adapted to expel toothpaste through the outflow hole. The piston has a screwthreaded central hole into which is screwed a screwthreaded rod one end of which passes through a stopper at the end of the second part opposite that with the outflow hole and which is fastened to the means for actuating the piston, which are formed by a plunger.
The above toothbrush is of simple construction and, when the two parts are separated, allows toothpaste to be applied to the bristles and the teeth to be brushed, the toothbrush and the toothpaste being carried in a jacket pocket or handbag.
However, the outflow of toothpaste is effected by unscrewing the plunger to move it away from the reservoir and then pushing the plunger axially towards the reservoir, which directly causes axial displacement of the piston and outflow of toothpaste. It can therefore be seen that the quantity of toothpaste that flows out will depend on the number of turns through which the plunger has been rotated, in other words on the distance established between the plunger and the reservoir.
However, users will generally attempt to operate the plunger with only one hand, the other hand holding the brush part. As a result the amount of toothpaste that the user applies to the bristles will vary considerably from one use to another, and can be excessive. This excess toothpaste will result in accelerated emptying of the reservoir, whose volume is necessarily limited because of its small dimensions. The user will therefore have to replace the reservoir of toothpaste too soon, which makes the toothbrush less agreeable to use.
The object of the present invention is to remedy the drawbacks of the toothbrush described hereinabove by providing a toothbrush with a toothpaste metering device.
The toothbrush according to the invention is of the type having a hollow handle adapted to be filled with toothpaste and a brush part with bristles, the handle and the brush part having means for fixing them together end-to-end. The handle forms a reservoir for the toothpaste and has at a first end an outflow hole for the toothpaste and at a second end means for actuating a piston housed in the reservoir and adapted to expel the toothpaste through the outflow hole. The piston has a screwthreaded central hole co-operating with a screwthreaded rod one end of which passes through a stopper at the second end of the reservoir and is fastened to a knob for actuating the piston, the screwthreaded rod and the actuator knob being mobile in rotation and in translation.
The toothbrush according to the invention includes means for limiting the axial travel of the piston disposed between the piston and the stopper and fastened axially to the rod. The volume of toothpaste expelled by the piston is proportional to the axial travel of said piston and limiting its axial travel therefore limits the quantity of toothpaste applied to the brush part.
In one embodiment of the invention the means for limiting the travel of the piston are prevented from rotating relative to the rod. The screwthreaded rod and the means for limiting the travel of the piston can be in one piece.
The means for limiting the travel of the piston advantageously include a disc whose diameter is greater than that of the screwthreaded rod and which has an abutment surface adapted to come into contact with a corresponding surface of the stopper. Thus, when the user turns the actuator knob, the screwthreaded rod and the disc move with a helicoidal motion and the actuator knob moves away from the reservoir. When the screwthreaded rod and the disc have travelled a distance corresponding to the predetermined dose, the disc comes into contact with the stopper, which immobilizes it. The abutment surfaces of the disc and the stopper can be provided with lugs designed to prevent the disc rotating relative to the stopper after they come into contact.
In one embodiment of the invention the disc is at a maximum distance from the stopper of 1.7 mm, for example, and this distance is proportional to the required volume of toothpaste.
The actuator knob is mobile in translation and in rotation and is fastened to the screwthreaded rod.
The invention provides a toothbrush which has a reserve of toothpaste enabling a given number of uses. The user knows in advance how many times they can brush their teeth with the toothbrush. A system can be provided to indicate the number of brushings remaining, for example by providing the body of the reservoir with a graduated transparent wall portion through which the user can see the piston.